Modeling spatula



June 13, 1950 A. M. BARROSO MODELING SPATULA Filed July 23, 1948 INVENTOR. ALBERTQ MORIN BARROSO FIG.

BY wycyb Patented June 13, 1950 UNITED PATENT OFFICE MODELING SPATULA AlbertozMorin- Barroso, Los Halos, Cuba Application Judas-194s; Serial No. 40 272 InCuba August 13"; 1947- The present invention relates to modell ng a spatulae in. general and moreispecificallyto those employed in: dental worln As. is. well known, in the modelling-of dental? work two different types of; conditions met with, one in which the modelling: instrumentmust be heated Within certainlimlts andkept atthat temperature during relatively long periods ofztime and the other in; which the; heating: ofithe'tool mustof necessity. be intermittent, These cone ditions are governedbytwo.principalifacts which are; the nature of the work that is ubeingzdone;

and. the class of-material employed:

From the earliest time the work of thedentist'v in this field hasbe'enhampered by thenlack of adequate tools and the efforts to: eliminate that inconvenience have led'to the productionof numerous types of modelling spatul-aelwhich fromthe operators viewpoint, carr-all-be classed ill-two The: firstzgroupincludes all" principal groups. spatulae inwhich the heating element is not con tained in the spatula; to this group-belong 'all:

those that require to lac-:heated over aspirit lamp,

gas burner or the like. ln'thel second group are classed all the spatulae in whiohzthe heatingelea ment is incorporated in thespatula, generally in. the blade element; atpresent-this group-iscomsively in cases where theapplication:ofzheatimust' be intermittent while, ontheptherhandthe ones.- included in the second group are generallyv used? when a continuous application ofheat is required;

for though they can be-used inintermittentwork.

theyarenot well adapted for it; One ofgthe principal defects of all knownspatulaeis,that none,

of: them can beemployedas a two, purpose instrument, that is, thatnoneof them; is equally, eflicient in both' of the typeset work-mentioned and this lack. of adaptability results ;in-great;.in

convenience to the worker who; is obliged to change constantly from onespatulaytoi another.

One of the principal objectsofathe presentinvention is to provide a two; purpose electrical spatula that can advantageously replace the modelling spatulae and, the heating-system now employed by the dentist and. the; prosthesis worker.

trived that it furnishes the opcratorwithamodeh ling: instrument which, due to its, specific construction and the incorporation of the heatingelementin the blade,the latter instantly acquiresthe necessarytemperature for performing its worlcin the most advantageous manner when gutta-perc-ha, wax, paraffin, etc., are employed;

Still: another objective is to provide an electrical; spatula, the temperature of which can be regulated inaccordanc with the, type of work to be performed and the class ofmaterial that is beingused.

Aiurther-object oftheinvention is to provide a doublepurpos spatula which allows the operator--to-change instantly from one type of work tov the; other without the necessityof performing any complicated change or. losing an instant of time.

An, additional object of 'the invention is to provide a. spatula -characterized by the fact that the novel details of construction included in the blade, in, combination with the electrical circuit employed, permit the operator to not only he'at'the blade eithercontinuously or intermittently but also. tochoose the temperature-best suited for the work.

Othenobjects and advantages of my invention will beeasily-appreciated, hythose expert in the art, duringthercourseyof thisspecification with the. help of, the annexed drawings in which eachpart is represented by the same reference character in the-difierent views.

In theldrawings:

Figure-l is atop viewof the-current regulating member which at times-can also be employed as a heatingmember Figure 2lis a vertical section along the line 2-4 oiFigure 1;

Figure 3 .is a perspective view showing the spatula member inserted between the terminals of an electriccircuit contained in said current regulating member;

Figure 4 ,showsa modificationof the terminals of Figure 3;

Figure 5"is a lateral view, partly sectional, of the spatulamember.

Figure 6 is a top view of the spatula blade, partly broken away and on a larger scale, showing dctailsof' the different elements included in the blade.

Figure is across sectional view, on a slightly larger scale, of: the spatula handle along the line 1-1 ofFigure5; and

Figuretzis a section, on a larger scale, along the final?!) 10f. Figure 6.

In the preferred embodiment of my invention,-

illustrated in the drawings, l indicates the blade member of the spatula, said member comprising the combination of metallic element 2, which is a good conductor of both heat and electricity, with the included and spaced metallic elements 3 which are poor conductors of electricity. The element 2 may be made from any of the w llknown metals which are good conductors of heat and electricity, such as silver, copper, etc. The elements 3 may be made of any suitable metal or alloy which is a poor conductor of electricity, as for example: Nichrome, and other nickel, chromium and nickel-chromium-iron alloys, etc. The

elements 3 are contained in the lateral edges of said element 2 and firmly attached in direct electrical contact with it by any suitable means while projecting out slightly from the edges of said element 2, said elements 3 extending forward along the lateral edges of element 2 to points relatively near its end, then curving inwards :and then backwards as illustrated in Figure 6 by the broken lines, said elements 3 project backwards from the base of element 2 in order to form the terminal 3 to which electrical conductors 4 are firmly attached, said conductors 4 being preferably of larger diameters than terminal 3, said conductors 4 then extend backwards within the handle of the spatula and are surrounded and completely insulated b refractory material 5 enclosed in casing 6 forming the spatula handle, said casing being closed at the end furthest from the spatula blade by a removable cap I provided on its inner face with metallic pins -3 that penetrate tube-like receptacles forming the terminals of conductors 4 to establish an electrical connection between said conductors I and conductor wires 9 that extend from said pins 8 to plug It furnished with contacts Iii which can be plugged in on any of the different electrical circuits included in the current regulating member.

The current regulating member of the combination comprises a cylindrical casing or shell Il enclosing electrical transformer l2 which can be connected to any suitable source of electrical energy by conductors I2, said casing II having on its upper portion I3 two spaced and projecting elements I4, said elements, which form the metallic terminals of an electric circuit, are insulated from each other and from said casing and are attached to portion I3 of the latter by screws I5, said terminals l4 being connected by leads I6 to the secondary circuit of transformer I2. The other portion of casing II presents openings I1 and I7 through which contacts I0 of plug It penetrate to establish contact with circuits formed by tapping the secondary winding of the transformer I2, thus permitting the user of the spatula to obtain the current best suited for the work.

From the foregoing it is seen that the invention covers an instrument which comprises the combination of a spatula member, which includes a novel type of heating element, and a current regulating and heat applying member, said combination being so designed that said members are interdependent to such an extent that the principal object of the invention, the production of a double purpose instrument, can not be obtained in the absence of one of said members.

As has already been said, the instrument is equally suitable for work requiring an intermittent application of heat or for the class of work in which the application of heat must be continuous.

In the first case the procedure is as follows: The blade of the spatula is thrust between terminals I4 that project from upper portion I3 of casing ll, said terminals being so spaced that when the blade of the spatula is thrust between them each one of elements 3 lodged in the edges of the spatula and projecting outward from them, is firmly pressed against one of said terminals I4 thus closing the circuit and allowing the current to flow from one of the terminals to the resistance element 3 in contact with it then through metallic element 2 to the other resistance element-3 and from this to the other terminal of the circuit, and due to the resistance offered to the passage of the current by said two elements 3-, heat is generated in them and is transmitted by contact to element 2 thus raising its temperature to the required point.

When it is required to maintain the spatula heated continuously the spatula circuit is simply plugged in at whichever of the circuits ending at I! or IT furnishes the current best suited for the work thereby establishing a flow of current through one of the wires 9 and a connector 8 to one of the resistance elements 3, across element 2 to the other resistance element 3, then to conductor 8 and wire 9 to the current regulating member.

I have found that in both of the heating processes mentioned the blade of the spatula is raised to the required temperature almost instantly and that the change from one to the other can be made in a few seconds under normal working conditions.

Although the inclusion of the resistance ele-' ments in the sides of the spatula blade can be performed in any suitable manner, I have discovered that the best results are obtained when the previously formed resistance elements are set up within a suitable mold and the metal that is to form the blade is poured in a molten condition into said mold or, in other words, when the blade metal is cast on the resistance elements in such a manner that the latter occupy the positions shown in the drawings. This constructional detail is specially noteworthy because it represents a complete departure from all the methods previously employed for attaching the resistance element to the blade of the spatula. Up to the present it has been usual to insert some insulating material like asbestos, porcelain, etc. between the resistance and the blade, so that the current will only circulate through the resistance or stated differently, that the blade element does not form part of the electric circuit.

This insulation introduced between the heating element or resistance and the blade of the spatula makes the operation of heating the latter slower and at the same time introduces an element of weakness in the union of said parts. By casting the blade directly on the spaced resistance not only do I obtain a stronger and more permanent union but also establish direct electrical contact between said resistance elements and the blade which thus forms part of the circult in which the current circulates, something entirely new, and as I have found out by numerous trials and experiments the excellence of the thermal contact so established is such that the blade is heated in a fraction of the time required by the methods usually employed.

Both the foregoing description and the an-' nexed drawings refer only to a particular embodiment of the invention for, as anyone versed in the art can easily see, the combination del scribed admits several constructive changes without departing from the spirit of the invention. Thus, for example, instead of using plug l0 and inlet apertures l1 and IT to connect the spatula blade circuit to the different circuits formed with the leads !8 of the taps in the secondary winding of transformer [2, a suitable switch may be installed on casing II for the purpose, thus making the connections of conductors 9 with the current regulating member of the combination permanent.

Having disclosed my invention and given a detailed description of a preferred embodiment, I claim:

1. Improvement in modelling spatula comprising in combination, a metallic blade element substantially enclosing two spaced metallic elements of lower electrical conductivity extending along the lateral edges of said blade element and projecting slightly from said edges, said low electrical conductivity elements being attached at their rear ends to electrical conductors that connect them to a current regulating member which is in turn connected to a source of electrical energy.

2. Improvement in modelling spatula as in claim 1, characterized by the fact that the portions of said metallic elements of low electrical conductivity included in the edges of said metallic blade element are in direct electrical contact with said blade element and extend from its base to points situated near its end.

3. Improvement in modelling spatula as in claim 1, characterized by the fact that said current regulating member of the combination comprises a casing, an electric transformer within said casing, electric circuits of different voltages formed by tapping the secondary winding of said transformer, the terminals of said circuits being brought to said casing at points suitable for connecting them by means of conductors passing through the handle of the spatula to the heating circuit in the spatula blade, an additional electric circuit formed with the secondary winding of said transformer, said circuit having insulated and spaced metallic terminals that project out from said casing; and means for conmeeting the primary circuit of said electric transformer to a source of electrical energy.

ALBERTO MORIN BARROSO.

REFERENCES CITED The following references are of record in the of this patent:

UNITED STATES PATENTS Number Name Date 2,051,759 Turpin et a1 Aug. 18, 1936 2,411,549 Lindberg Nov. 26, 1946 2,427,209 Hagadorn Sept. 9, 1947 

